Heat and ozone resistance of Bacillus spores isolated from laboratory animals

Heat resistance of free-spores of 78 Bacillus strains isolated from laboratory animals was examined. Spores of 41 out of 78 strains survived for 320 minutes at 70 degrees C, 27 for 160 min, at 100 degrees C, only one for 20 min. at 110 degrees C by autoclaving, and none for 5 min. at 120 degrees C. D-values at 100 degrees C of 9 strains determined were between 5.03 and 30.06 min. Spores of 9 strains from stock cultures were exposed to ozone gas at various conditions. Ozone resistance of spores was closely dependent upon relative humidity. D-values of the spores tested by treatment with 200 ppm ozone at 60% RH were over 200 min., especially over 1,000 min. in 4 strains, indicating that exposure to ozone at a moderate humidity for 6 hours could not sterilize Bacillus spores. At 90% RH, however, treatment with 200 ppm ozone for 6 hr. might be effective for a routine sterilization in laboratory animal facilities.     

Cage RACK ventilation options for laboratory animal facilities

Individually ventilated cage systems have become the method of choice for housing rodents. The author describes the various options for cage ventilation, from using supply and exhaust fans to directly connecting the racks to the building ventilation system.     

Air-borne dust and its protein in laboratory animal facilities

Atopic individuals who were exposed to dust in animal rooms for a long time were more likely than non-atopics to have animal-related symptoms. Standard skin prick tests were performed using crude antigens from dander and urine, and 75 to 100% of atopic persons had positive skin reactions. It seems that allergens in animal rooms result from air-borne dust and the dust originates in animal urine and dander. The protein content occurs as dust particles both below and above 10 micron in diameter. The dust particles above 10 micron cannot pass through face masks, so half of the dust protein is arrested under the mask, but smaller particles pass through. In order to minimize the symptoms, we need to improve the design of cages, animal rooms, experimental rooms, ventilation systems and other protective equipment.     

Monitoring of antibiotic resistance in bacteria isolated from laboratory animals

The drug resistance of microorganisms isolated from laboratory animals never treated with antibiotics is being reported consistently, while the number of laboratory animals used in medicine, pharmacy, veterinary medicine, agriculture, nutrition, and environmental and health science has increased rapidly in Korea. Therefore, this study examined the development of antimicrobial resistance in bacteria isolated from laboratory animals bred in Korea. A total of 443 isolates (7 species) containing 5 Sphingomonas paucimobilis, 206 Escherichia coli, 60 Staphylococcus aureus, 15 Staphylococcus epidermidis, 77 Enterococcus faecalis, 27 Citrobacter freundii, 35 Acinetobacter baumannii were collected from the nose, intestine, bronchus and reproductive organs of ICR mice and SD rats. Of these species, Acinetobacter baumannii and Enterococcus faecalis showed significant antimicrobial resistance according to the minimum inhibition concentration (MIC) in E-test. In case of Acinetobacter baumannii, several isolates showed MIC values 16-128 μg/mL for cefazolin and cefoxitin, and higher resistance (128-512 μg/mL) to nitrofurantoin than that of standard type. Resistance to cefazolin, cefoxitin and nitrofurantoin was detected in 17.14, 20.00, and 8.57% of the Acinetobacter baumannii isolates, respectively. In addition, 44.1% of the Enterococcus faecalis isolates collected from the laboratory animals were resistant to oxacillin concentration of 16-32 μg/mL range, while MIC value of standard type was below oxacillin concentration of 6 μg/mL. These results suggest that in rodent species of laboratory animals, Acinetobacter baumannii are resistance to cefazolin, cefoxitin and nitrofurantoin, whereas those of Enterococcus faecalis were resistance to oxacillin.     

A user-friendly approach to cost accounting in laboratory animal facilities

Cost accounting is an essential management activity for laboratory animal facility management. In this report, the author describes basic principles of cost accounting and outlines steps for carrying out cost accounting in laboratory animal facilities. Methods of post hoc cost accounting analysis for maximizing the efficiency of facility operations are also described.     

Heat resistance of Lactobacillus spp. isolated from Cheddar cheese

Mesophilic Lactobacillus spp. are the dominant organisms in mature Cheddar cheese. The heat resistance of broth grown cultures of Lactobacillus plantarum DPC1919 at temperatures between 50 and 57.5 degrees C, Lact. plantarum DPC2102 at temperatures between 48 and 56 degrees C and Lact. paracasei DPC2103 at temperatures between 50 and 67.5 degrees C was determined. The z-values for Lact. plantarum DPC1919, Lact. Plantarum DPC2102 and Lact. paracasei DPC2103 were 6.7 degrees C, 6.2 degrees C and 5.3 degrees C, respectively. Lactobacillus paracasei DPC2103 showed evidence of injury and recovery, especially at higher temperatures. Milk grown cultures of strains DPC2102 and DPC2103 showed greater heat resistance than broth grown cultures, tailing of the death curves and a nonlinear z-curve. Of the three strains, Lact. paracasei DPC2103 had the potential to survive pasteurization temperatures, whether grown in milk or broth.     

Pathogenicity of Sporotrichum pruinosum and Cladosporium oxysporum,isolated from the bronchial secretions of a patient,for laboratory mice

In this study we have demonstrated the occurrence of Sporotrichum pruinosum and Cladosporium oxysporum in the bronchial secretions of a patient with a presumptive diagnosis of tuberculosis. This observation coupled with the ability of both fungi to cause infection and elicit tissue responses in experimentally infected mice supported a probable etiologic relationship with the patient which could not be confirmed in the absence of histologic evidence. In vitro some antimycotics were tested against S. pruinosum and C. oxysporum by the agar dilution method. Oxiconazole with a minimum inhibitory concentration of 0.1 g/ml^–1 after 72 h and amorolfine at a concentration of 0.001 g/ml^–1 after 72 h were the most active ones against S. pruinosum and C. oxysporum respectively. It is suggested that the isolation of S. pruinosum and C. oxysporum from patients with bronchopulmonary disorders should be viewed with caution. Clinical and laboratory evaluation of such patients should be done critically before arriving at a firm diagnosis.     

Antibiotic resistance in bacterial isolates from laboratory animal colonies naive to antibiotic treatment

Antiobiogrammes were made of a number of isolates of Staphylococcus aureus, Escherichia coli and Pasteurella pneumotropica derived from rodent, rabbit or minipig colonies never treated with antibiotics. For S. aureus no differences between rats and mice were found in the percentage of resistant isolates. Gentamicin and erythromycin were found to be the most efficient, while the highest percentages of resistance were found to be against penicillins and sulphonamides. In general, the results from antibiogrammes on E. coli were rather uniform, with only slight differences between isolates from different species, except that more vancomycin and tetracycline-resistant minipig isolates were found. In almost all isolates of E. coli, resistance was shown against penicillin, fucidin, macrolides, lincosamides and tiamulin. For a number of antibiotics, mouse isolates of P. pneumotropica were more frequently found to be sensitive than rat isolates. The resistance patterns of E. coli from the minipigs were quite similar to resistance patterns found in farm pigs, but apart from this, the resistance patterns of the bacterial species tested did not resemble human or farm animal patterns in any of the animal species, and, therefore, these studies do not support the theory that S. aureus and E. coli in laboratory animal colonies derive from the normal flora of the human caretakers. The fact that rodent species of E. coli, in contrast to human and farm animal species, are sensitive to ampicillin, tetracyclines, and the combination of sulphonamides and trimethoprim, might be due to the fact that these antibiotics are not used in rodent populations.     

湖北省实验动物设施环境控制中存在的问题

目的分析总结湖北省2012年度实验动物许可单位年检中环境设施的检测结果,找出问题,提出促进湖北省实验动物环境设施可靠运行的建议。方法各实验动物环境设施采用30%区域抽检方式,依据GB14925-2010《实验动物环境及设施》,进行环境指标检测。结果除气流速度、沉降菌最大平均浓度外,其他技术指标均存在不符合国家标准的情况。结论应针对实验动物设施管理加强培训,提高实验动物设施管理人员的管理水平,从而保证实验动物设施的正常运行。     

Spectrophotometric method of determining the osmotic resistance of lysosomes isolated from animal tissue

Rapid spectrophotometric determination of animal tissue lysosome osmoresistance is described. The duration of analysis is decreased by 5-6 h, as compared to enzymatic method. The process of lysosome degradation was linear at 0.7 M sucrose concentration. The dependence of sucrose molarity on the extent of lysosome lysis was complex. The lysosome lysis rate rapidly increased at sucrose molarity less than 0.7 M. Lysosome incubation at 0.4 degrees C for 24 h increased their osmotic sensitivity within the whole investigated osmotic pressure range. Isolated lysosome osmoresistance may be used as an index of dynamic structural and functional state of these particles and the extent of their degradation caused by various physical and chemical factors in vivo and in vitro. The measure of the initial absorption (A520) and the initial lysosome lysis rate (delta A520/min), as well as biological half-life may be the index of such an effect.     

Dermatophytes isolated from laboratory animals

In order to determine the presence of dermatophytes in healthy skin, 200 animals from the animal house of Faculty of Medicine, U.N.A.M., were studied; these were 50 rats, 50 rabbits, 50 mice, and 50 guinea pigs. Out of these 200 animals, 29.5% had positive isolation of Trichophyton mentagrophytes, var. lacticolor. The frequency variation was: rats, 68%; rabbits, 36%; mice, 8%; and guinea pigs, 6%. Male rats and male rabbits, had the higher incidence of positives. The epidemiologic repercussion of these and the significance to use these animals in biomedical investigation is discussed.     

Sequencing of Cladosporium sphaerospermum, a Dematiaceous fungus isolated from blood culture

Cladosporium sphaerospermum is one of the most widely distributed allergens causing serious problems in patients with respiratory tract disease. We report the 26,644,473-bp draft genome sequence and gene annotation of C. sphaerospermum UM843. Analysis of the genome sequence led to the finding of genes associated with C. sphaerospermum's melanin biosynthesis, allergens, and antifungal drug resistance.     

Financial control of laboratory animal facilities: partial cost recovery in an academic institution.

The objective of cost management in the animal house is to make efficient use of resources and to regulate the activity of the user. Regular charging of users keeps them aware of their responsibility both ethically and financially. Forward budgetary control is encouraged and regulation of the work load achieved through planned requirements helps to reduce animal wastage.     

Amoebae isolated from laboratory eyewash stations

Amoebae potentially able to cause severe eye infections were isolated from 31 of 56 eyewash stations. Eyewash stations that contained a reservoir presented a greater hazard than those without a reservoir. The need to flush eyewash stations regularly as part of safe laboratory practices is emphasized.     

Heat resistance of ileal loop reactive Bacillus cereus strains isolated from commercially canned food.

Sporeformers isolated from a commercially canned food were identified as Bacillus cereus, lactose-positive variants. The thermal resistance of spore crops produced from each of two representative cultures was determined in 0.067 M phosphate buffer at pH 7.0. The D121.1 values for one isolate were approximately 0.03 min (z = 9.9C), whereas the D121.1 values for the other isolate were 2.35 min (z = 7.9 C). Thermal inactivation results for heat-stressed isolates from each strain showed no significant alteration in heat resistance from that of the two parent spore crops. Both isolates were reactive when injected into the ligated rabbit ileum.